This rare mushroom looks like a gorgeous, reticulate version of the more common and better known Boletus bicolor. The red and yellow colors are offset nicely by the indigo blue bruising. Microscopic features for Boletus speciosus include rather long and narrow spores, and a trichodermial pileipellis. I have only seen this species once, about 10 years ago, and on that day the photography gods were not my friends; I apologize for the terrible depth-of-field issues in the photo.

Boletus pseudopeckii is similar but less brightly colored; its rusty red cap soon fades to tan (it also features a cutis rather than a trichoderm). Another look-alike, Boletus peckii, has a bitter taste and much shorter (9-12 µ spores). A brown variety, Boletus speciosus var. brunneus has a brown cap and is otherwise similar; some authors (e.g. Roody, 2003) suspect it to be the same as Boletus psuedopeckii.

Boletus speciosus was originally described from New York (Frost, 1874), and is apparently fairly widespread in eastern North America's hardwood forests. The Europeans have applied the name to a very similar species found in Switzerland and northern Italy; whether or not it is actually the same as the North American species is not clear. As described by Breitenbach & Kränzlin (1991), it has much wider spores and more brown in the cap than the species described and illustrated here.

My specimens, described below, were significantly smaller than the robust mushrooms featured in most descriptions; generally the cap dimensions are reported as 8-15 cm across, with stem dimensions as 5-13 x 1.5-4 cm (Smith, Smith & Weber, 1981).

Description:

Ecology: Mycorrhizal with oaks and other hardwoods; growing alone or scattered; summer and fall; rare; apparently widely distributed in eastern North America. The illustrated and described collection is from Illinois.